The Experts below are selected from a list of 57093 Experts worldwide ranked by ideXlab platform
Irene Marzolff - One of the best experts on this subject based on the ideXlab platform.
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piping as a process of gully erosion in small format Aerial pothography a short note
Cuadernos de investigación geográfica Geographical Research Letters, 2011Co-Authors: Irene Marzolff, Johannes B. RiesAbstract:Piping is one of the geomorphologic processes that are most difficult to quantify, because it can hardly be examined by conventional field survey methods and just as little by most remote sensing methods. Bridging the resolution gap between terrestrial and conventional Aerial Photography, small-format Aerial Photography taken by unmanned platforms from low flying heights (50-500 m) has proven to be an excellent tool for gully erosion monitoring in several research studies conducted by the authors (e.g. Marzolff and Ries, 2007; Aber et al., 2010; Marzolff et al., 2011). This kind of high-resolution photo-monitoring also enables the documentation of piping forms and provides clues to the process dynamics and to the function of piping as an initializing process for gully incision/erosion.
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small format Aerial Photography principles techniques and geoscience applications
2010Co-Authors: James S Aber, Irene Marzolff, Johannes B. RiesAbstract:As the need for geographical data rapidly expands in the 21st century, so too do applications of small-format Aerial Photography for a wide range of scientific, commercial and governmental purposes. Small-format Aerial Photography (SFAP)presents basic and advanced principles and techniques with an emphasis on digital cameras. Unmanned platforms are described in considerable detail, including kites, helium and hot-air blimps, model airplanes, and paragliders. Several case studies, primarily drawn from the geosciences, are presented to demonstrate how SFAP is actually used in various applications. Many of these integrate SFAP with ground-based investigations as well as conventional large-format Aerial Photography, satellite imagery, and other kinds of geographic information. Full-color photographs throughoutCase studies from around the globeTechniques presented allow for image resolution impossible to match via traditional Aerial Photography or satellite datasetsGlossary clarifies key terms
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basic principles of small format Aerial Photography
Small-Format Aerial Photography#R##N#Principles Techniques and Geoscience Applications, 2010Co-Authors: James S Aber, Irene Marzolff, Johannes B. RiesAbstract:Small-format Aerial Photography is based primarily on solar radiation reflected from the Earth's surface in the visible and near-infrared portions of the spectrum. SFAP is a compromise between ideal photographic conditions and the reality of what is possible to accomplish under natural conditions within logistical constraints and financial limitations. A single photograph has geometric characteristics similar to the picture sensed through a single human eye, which creates a single-point perspective view. Two overlapping views of the same area result in stereoscopic imagery in which depth perception is apparent. This is the basis for much photointerpretation as well as photogrammetry. Photographic information consists of both the primary image data as well as metadata about the image. Metadata includes date of image acquisition, location, type of camera and lens, and other relevant information. This metadata should be saved in a manner that is difficult to separate from the image data.
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Monitoring of gully erosion in the Central Ebro Basin by large-scale Aerial Photography taken from a remotely controlled blimp
Catena, 2003Co-Authors: Johannes B. Ries, Irene MarzolffAbstract:Large deep gullies (Span. barrancos) are some of the most important sediment sources in the semi-arid environment of the Central Ebro Basin. They are incised into the Quaternary valley bottoms (Span. vales), which are characteristic landforms in this area. In the research project EPRODESERT (Evaluation of Processes Leading to Land Degradation and Desertification under Extensified Farming Systems), the development of a large barranco system is being investigated by different methods, including documentation and monitoring by Aerial Photography. Geomorphological forms and processes, such as sheet wash, rill and gully erosion, cannot be documented sufficiently by conventional remote sensing methods. Spatial and temporal resolution of satellite sensors as well as of conventional Aerial Photography do not correspond to the scale and dynamics of geomorphological processes. With a specially designed hot-air blimp as a sensor platform, large-scale Aerial photographs were obtained from the Barranco de las Lenas specifically aimed at the scientific demands (very high spatial and temporal resolution). The development of the gully is documented and its dynamics are evaluated by a sequence of six Aerial photographs taken between 1995 and 1998. © 2003 Elsevier Science B.V. All rights reserved.
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monitoring of gully erosion in the central ebro basin by large scale Aerial Photography taken from a remotely controlled blimp
Catena, 2003Co-Authors: Johannes B. Ries, Irene MarzolffAbstract:Abstract Large deep gullies (Span. barrancos) are some of the most important sediment sources in the semi-arid environment of the Central Ebro Basin. They are incised into the Quaternary valley bottoms (Span. vales), which are characteristic landforms in this area. In the research project EPRODESERT ( E valuation of Pro cesses Leading to Land Degradation and Desert ification under Extensified Farming Systems), the development of a large barranco system is being investigated by different methods, including documentation and monitoring by Aerial Photography. Geomorphological forms and processes, such as sheet wash, rill and gully erosion, cannot be documented sufficiently by conventional remote sensing methods. Spatial and temporal resolution of satellite sensors as well as of conventional Aerial Photography do not correspond to the scale and dynamics of geomorphological processes. With a specially designed hot-air blimp as a sensor platform, large-scale Aerial photographs were obtained from the Barranco de las Lenas specifically aimed at the scientific demands (very high spatial and temporal resolution). The development of the gully is documented and its dynamics are evaluated by a sequence of six Aerial photographs taken between 1995 and 1998.
Morgana Vighi - One of the best experts on this subject based on the ideXlab platform.
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who s better at spotting a comparison between Aerial Photography and observer based methods to monitor floating marine litter and marine mega fauna
Environmental Pollution, 2020Co-Authors: Odei Garciagarin, Patricia Gozalbes, Ohiana Revuelta, María Luisa Honrubia Serrano, Jaime Penadessuay, Agustin Lobo, Alex Aguilar, Asuncion Borrell, Juan Antonio Raga, Morgana VighiAbstract:Abstract Pollution by marine litter is raising major concerns due to its potential impact on marine biodiversity and, above all, on endangered mega-fauna species, such as cetaceans and sea turtles. The density and distribution of marine litter and mega-fauna have been traditionally monitored through observer-based methods, yet the advent of new technologies has introduced Aerial Photography as an alternative monitoring method. However, to integrate results produced by different monitoring techniques and consider the photographic method a viable alternative, this ‘new’ methodology must be validated. This study aims to compare observations obtained from the concurrent application of observer-based and photographic methods during Aerial surveys. To do so, a Partenavia P-68 aircraft equipped with an RGB sensor was used to monitor the waters off the Spanish Mediterranean coast along 12 transects (941 km). Over 10000 images were collected and checked manually by a photo-interpreter to detect potential targets, which were classified as floating marine macro-litter, mega-fauna and seabirds. The two methods allowed the detection of items from the three categories and proved equally effective for the detection of cetaceans, sea turtles and large fish on the sea surface. However, the photographic method was more effective for floating litter detection and the observer-based method was more effective for seabird detection. These results provide the first validation of the use of Aerial Photography to monitor floating litter and mega-fauna over the marine surface.
Johannes B. Ries - One of the best experts on this subject based on the ideXlab platform.
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piping as a process of gully erosion in small format Aerial pothography a short note
Cuadernos de investigación geográfica Geographical Research Letters, 2011Co-Authors: Irene Marzolff, Johannes B. RiesAbstract:Piping is one of the geomorphologic processes that are most difficult to quantify, because it can hardly be examined by conventional field survey methods and just as little by most remote sensing methods. Bridging the resolution gap between terrestrial and conventional Aerial Photography, small-format Aerial Photography taken by unmanned platforms from low flying heights (50-500 m) has proven to be an excellent tool for gully erosion monitoring in several research studies conducted by the authors (e.g. Marzolff and Ries, 2007; Aber et al., 2010; Marzolff et al., 2011). This kind of high-resolution photo-monitoring also enables the documentation of piping forms and provides clues to the process dynamics and to the function of piping as an initializing process for gully incision/erosion.
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small format Aerial Photography principles techniques and geoscience applications
2010Co-Authors: James S Aber, Irene Marzolff, Johannes B. RiesAbstract:As the need for geographical data rapidly expands in the 21st century, so too do applications of small-format Aerial Photography for a wide range of scientific, commercial and governmental purposes. Small-format Aerial Photography (SFAP)presents basic and advanced principles and techniques with an emphasis on digital cameras. Unmanned platforms are described in considerable detail, including kites, helium and hot-air blimps, model airplanes, and paragliders. Several case studies, primarily drawn from the geosciences, are presented to demonstrate how SFAP is actually used in various applications. Many of these integrate SFAP with ground-based investigations as well as conventional large-format Aerial Photography, satellite imagery, and other kinds of geographic information. Full-color photographs throughoutCase studies from around the globeTechniques presented allow for image resolution impossible to match via traditional Aerial Photography or satellite datasetsGlossary clarifies key terms
-
basic principles of small format Aerial Photography
Small-Format Aerial Photography#R##N#Principles Techniques and Geoscience Applications, 2010Co-Authors: James S Aber, Irene Marzolff, Johannes B. RiesAbstract:Small-format Aerial Photography is based primarily on solar radiation reflected from the Earth's surface in the visible and near-infrared portions of the spectrum. SFAP is a compromise between ideal photographic conditions and the reality of what is possible to accomplish under natural conditions within logistical constraints and financial limitations. A single photograph has geometric characteristics similar to the picture sensed through a single human eye, which creates a single-point perspective view. Two overlapping views of the same area result in stereoscopic imagery in which depth perception is apparent. This is the basis for much photointerpretation as well as photogrammetry. Photographic information consists of both the primary image data as well as metadata about the image. Metadata includes date of image acquisition, location, type of camera and lens, and other relevant information. This metadata should be saved in a manner that is difficult to separate from the image data.
-
Monitoring of gully erosion in the Central Ebro Basin by large-scale Aerial Photography taken from a remotely controlled blimp
Catena, 2003Co-Authors: Johannes B. Ries, Irene MarzolffAbstract:Large deep gullies (Span. barrancos) are some of the most important sediment sources in the semi-arid environment of the Central Ebro Basin. They are incised into the Quaternary valley bottoms (Span. vales), which are characteristic landforms in this area. In the research project EPRODESERT (Evaluation of Processes Leading to Land Degradation and Desertification under Extensified Farming Systems), the development of a large barranco system is being investigated by different methods, including documentation and monitoring by Aerial Photography. Geomorphological forms and processes, such as sheet wash, rill and gully erosion, cannot be documented sufficiently by conventional remote sensing methods. Spatial and temporal resolution of satellite sensors as well as of conventional Aerial Photography do not correspond to the scale and dynamics of geomorphological processes. With a specially designed hot-air blimp as a sensor platform, large-scale Aerial photographs were obtained from the Barranco de las Lenas specifically aimed at the scientific demands (very high spatial and temporal resolution). The development of the gully is documented and its dynamics are evaluated by a sequence of six Aerial photographs taken between 1995 and 1998. © 2003 Elsevier Science B.V. All rights reserved.
-
monitoring of gully erosion in the central ebro basin by large scale Aerial Photography taken from a remotely controlled blimp
Catena, 2003Co-Authors: Johannes B. Ries, Irene MarzolffAbstract:Abstract Large deep gullies (Span. barrancos) are some of the most important sediment sources in the semi-arid environment of the Central Ebro Basin. They are incised into the Quaternary valley bottoms (Span. vales), which are characteristic landforms in this area. In the research project EPRODESERT ( E valuation of Pro cesses Leading to Land Degradation and Desert ification under Extensified Farming Systems), the development of a large barranco system is being investigated by different methods, including documentation and monitoring by Aerial Photography. Geomorphological forms and processes, such as sheet wash, rill and gully erosion, cannot be documented sufficiently by conventional remote sensing methods. Spatial and temporal resolution of satellite sensors as well as of conventional Aerial Photography do not correspond to the scale and dynamics of geomorphological processes. With a specially designed hot-air blimp as a sensor platform, large-scale Aerial photographs were obtained from the Barranco de las Lenas specifically aimed at the scientific demands (very high spatial and temporal resolution). The development of the gully is documented and its dynamics are evaluated by a sequence of six Aerial photographs taken between 1995 and 1998.
Wageeh Boles - One of the best experts on this subject based on the ideXlab platform.
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investigation of fish eye lenses for small uav Aerial Photography
IEEE Transactions on Geoscience and Remote Sensing, 2009Co-Authors: Alex Gurtner, Duncan G Greer, Richard R Glassock, Luis Mejias, Rodney A Walker, Wageeh BolesAbstract:Aerial Photography obtained by unmanned Aerial vehicles (UAVs) is a rising market for their civil application. Small UAVs are believed to close gaps in niche markets, such as acquiring airborne image data for remote sensing purposes. Small UAVs can fly at low altitudes, in dangerous environments, and over long periods of time. However, their small lightweight construction leads to new problems, such as higher agility and more susceptibility to turbulence, which has a big impact on the quality of the data and their suitability for Aerial Photography. This paper investigates the use of fish-eye lenses to overcome field-of-view (FOV) issues for highly agile UAV platforms susceptible to turbulence. The fish-eye lens has the benefit of a large observation area (large FOV) and does not add additional weight to the aircraft, such as traditional mechanical stabilizing systems. We present the implementation of a fish-eye lens for Aerial Photography and mapping purposes, with potential use in remote sensing applications. We describe a detailed investigation from the fish-eye lens distortion to the registering of the images. Results of the process are presented using low-quality sensors typically found on small UAVs. The system was flown on a midsize platform (a more stable Cessna aircraft) and also on ARCAA's small (<10 kg) UAV platform. The effectiveness of the approach is compared for the two sized platforms.
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investigation of fish eye lenses for small uav Aerial Photography
Australian Research Centre for Aerospace Automation; Faculty of Built Environment and Engineering, 2008Co-Authors: Alex Gurtner, Duncan G Greer, Richard R Glassock, Luis Mejias, Rodney A Walker, Wageeh BolesAbstract:Aerial Photography obtained by UAVs (Unmanned Aerial Vehicles) is an emerging market for civil applications. Small UAVs are believed to close gaps in niche markets, such as acquiring airborne image data for remote sensing purposes. Small UAVs will be able to fly at low altitudes, in dangerous environments and over long periods of time. However, the small lightweight constructions of these UAVs lead to new problems, such as higher agility leading to more susceptibility to turbulence and limitations in space and payload for sensor systems. This research investigates the use of low-cost fisheye lenses to overcome such problems which theoretically makes the airborne imaging less sensitive to turbulence. The fisheye lens has the benet of a large observation area (large field of view) and doesn't add additional weight to the aircraft, like traditional mechanical stabilizing systems. This research presents the implementation of a fisheye lens for Aerial Photography and mapping purposes, including theoretical background of fisheye lenses. Based on the unique feature of the distortion being a function of the viewing angle, methods used to derive the fisheye lens distortion are presented. The lens distortion is used to rectify the fisheye images before these images can be used in Aerial Photography. A detailed investigation into the inner orientation of the camera and inertial sensor is given, as well as the registration of airborne collected images. It was found that the attitude estimation is critical towards accurate mapping using low quality sensors. A loosely coupled EKF filter applied to the GPS and inertial sensor data estimated the attitude to an accuracy of 3-5° (1-sigma) using low-cost sensors typically found in small UAVs. However, the use of image stitching techniques may improve the outcome. On the other hand, lens distortion caused by the fisheye lens can be addressed by rectification techniques and removed to a sub-pixel level. Results of the process present image sequences gathered from a piloted aircraft demonstrating the achieved performance and potential applications towards UAVs. Further, an unforeseen issue with a vibrating part in the lens lead to the need for vibration compensation. The vibration could be estimated to ±1 pixel in 75% of the cases by applying an extended Hough transform to the fisheye images.
Geert Verhoeven - One of the best experts on this subject based on the ideXlab platform.
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it s all about the format unleashing the power of raw Aerial Photography
Journal of remote sensing, 2010Co-Authors: Geert VerhoevenAbstract:Current one-shot, handheld Digital Still Cameras (DSCs) generally offer different file formats to save the captured frames: Joint Photographic Experts Group (JPEG), RAW and/or Tag(ged) Image File Format (TIFF). Although the JPEG file format is the most commonly used file format worldwide, it is incapable of storing all original data, something that also occurs, to a certain extent, for large TIFF files. Therefore, most professional photographers prefer shooting RAW files, often described as the digital Photography's equivalent of a film negative. As a RAW file contains the absolute maximum amount of information and original data generated by the sensor, it is the only scientifically justifiable file format. In addition, its tremendous flexibility in both processing and post-processing also makes it beneficial from a workflow and image quality point of view. On the other hand, large file sizes, the required software and proprietary file formats remain hurdles that are often too difficult to overcome for many photographers. Aerial photographers who shoot with handheld DSCs should be familiar with both RAW and other file formats, as their implications cannot be neglected. By outlining the complete process from photon capture to the generation of pixel values, additionally illustrated by real-world examples, the advantages and particularities of RAW Aerial Photography should become clear.
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providing an archaeological bird s eye view an overall picture of ground based means to execute low altitude Aerial Photography laap in archaeology
Archaeological Prospection, 2009Co-Authors: Geert VerhoevenAbstract:Since the beginning of Aerial Photography, researchers have used all kinds of devices ranging from pigeons, kites, poles and balloons to rockets in order to take cameras aloft and remotely gather Aerial data needed for a combination of research goals. To date, many of these unmanned devices are still used, mainly to gather archaeologically relevant information from relatively low altitudes, enabling so-called low-altitude Aerial Photography (LAAP). Besides providing a concise overview of the unmanned LAAP platforms commonly used in archaeological research, this paper considers the drawbacks and advantages of every device and provides an extensive reference list.
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helikite Aerial Photography a versatile means of unmanned radio controlled low altitude Aerial archaeology
Archaeological Prospection, 2009Co-Authors: Geert Verhoeven, Jo Loenders, Frank Vermeulen, Roald DocterAbstract:During the past 100 years, various devices have been developed and applied in order to acquire archaeologically useful Aerial imagery from low altitudes (e.g. balloons, kites, poles). This paper introduces Helikite Aerial Photography (HAP), a new form of close range Aerial Photography suitable for site or defined area Photography, based on a camera suspended from a Helikite: a combination of both a helium balloon and kite wings. By largely overcoming the drawbacks of conventional kite- and balloon-based Photography, HAP allows for a very versatile, remotely controlled approach to low-altitude Aerial Photography (LAAP). In addition to a detailed outline of the whole HAP system, its working procedure and possible improvements, some of the resulting imagery is shown to demonstrate the usefulness of HAP for several archaeological applications. Copyright © 2009 John Wiley & Sons, Ltd.